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Nitrous Oxide Emissions in Irrigated Corn as Affected by Nitrification Inhibitors
Author(s) -
Bronson K. F.,
Mosier A. R.,
Bishnoi S. R.
Publication year - 1992
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1992.03615995005600010025x
Subject(s) - nitrification , urea , nitrous oxide , chemistry , denitrification , agronomy , zoology , nitrogen , fertilizer , sowing , coated urea , carbon dioxide , environmental chemistry , biology , biochemistry , organic chemistry
Nitrous oxide and N 2 are the major denitrification products in irrigated corn ( Zea mays L.). In addition, N 2 O is considered a gas that contributes to global warming and stratospheric O 3 depletion. Minimizing N 2 O emissions in cropping systems is therefore an economic as well as an important environmental concern. In a 1989 field experiment, the nitrification inhibitor encapsulated calcium carbide (ECC) (0, 20, or 40 kg CaC 2 ha ‐1 ) or nitrapyrin (0.5 L a.i. ha ‐1 ) was banded with urea (218 kg N ha ‐1 ) 7 wk after planting corn. Between 1 and 14 wk after fertilization in 1989, N 2 O losses of 3226, 1109, 1017, and 1005 g N 2 O‐N ha ‐1 from urea alone, urea plus nitrapyrin, urea plus 20 kg ECC ha ‐1 , and urea plus 40 kg ECC ha ‐1 , respectively, were measured from vented chambers. Nitrous oxide fluxes were positively correlated with soil NO 3 levels, indicating that the nitrification inhibitors indirectly controlled N 2 O emissions by preventing NO 3 from accumulating in the soil. Carbon dioxide emissions from the root zone were generally not affected by ECC or nitrapyrin. In 1990, losses of N 2 O were less than in 1989 (1651 g N ha ‐1 with urea alone), probably because there were fewer irrigations. Nitrapyrin and ECC addition to urea resulted in 980 and 459 g N ha ‐1 N 2 O being emitted the second year. Nitrification inhibitors appear to be a useful tool in mitigating N 2 O emissions in agricultural systems.